Thyroid nodules Flashcards
definition of thyroid nodules
abnormal growths in the thyroid gland
epidemiology of thyroid nodules
present in 50% pop
palpable in 5-10% pop
more common in women
especially in iodine deficient regions
incidence increases with age
types of thyroid nodule
benign thyroid nodules
malignant thyroid nodules
benign thyroid nodules
thyroid adenomas
- follicular adenoma
- Hurthle cell adenoma
- toxic adenoma
- papillary adenoma
thyroid cyst
dominany nodules of multinodular goitres
hashimoto thyroiditis
malignant thyroid nodules
thyroid carcinoma
thyroid lymphoma
met cancer from breast/renal
RF for malignancy
male
extremities of age - <20yrs, >65yrs
history of radiation to head/neck
FH of thyroid cancer or polyposis
solid nodule
cold nodule
investigations for solitary thyroid nodule
thyroid US and TSH klevels
high or normal TSH do FNA
low TSH - thyroid scintigraphy - hot check = T3 and FT4 to assess cause of hyperthyroidism. Cold = FNA or monitoring
follicular adenoma
most common type of thyroid adenoma
10-15% are malignant
signs/symptoms - slow growing solitary nodule
can develop into toxic adenoma whoch produces thyropid hormones
Ix - FNA cant distinguish between follicular adenoma and ca, so thyroid surgery dx and rx
histology - normal follicular structure with no tumour invasioon into surrounding tissues eg capsule and bv
toxic adenoma
5-10% hyperthyroidism cases
30-50yrs
path - gain of func mutations in TSH receptor genem in single precurser cell = autonomous functioning of thyroid follicular cells of a single nodule = focal hyperplasia of thyroid follicular cells = toxic adenoma
overproduces thyroid hormones = hyperthyroid = decrease in TSH = suppression of hormone from rest of gland
sx - hyperthyroid
Ix - high T3 low TSH, thyroid scintigraphy - solitary hot nodule suppression of rest of the gland
toxic multinodular goitre
>60yrs
second most common cause of hyperthyroidism
develops in 10% of pts with long standing nodular goitre
path - chronic iodine deficiency/thyroid dysfunction = decreased hormone production = increased hypothalamic TRH secretion = persistent TSH stimulation of the thyroid gland = hyperplasia of thyroid nodules, some more active than others = (non-toxic) multinodular goitre
multiple somatic mutations of TSH receptor occur in long standing goitres >60% cases - autonomous functioning of some nodules (toxic) multinodular goitre = hyperthyroidism due to high T3 and T4
sx - hyperthyroidism and multinodular goitre
ix - high T3, low TSH, scintography - radioiodin euptake bt hyperfunctioning nodules with suppression of the rest of the gland
histopath - patches of enlarged follicular cells distended with colloid and with flattened epithelium
classification of thyroid cysts
simple cysts are exclusively fluid filled nodules lined by benign epithelial cells
complex cysts are partly solid and partly cystic and carry a 5-10% risk of malignancy
aetiology of thyroid cysts
50% due to cystic degeneration of thyroid tissue - colloid cyst
40% are due to involution of a follicular adenoma
10% are due to thyroid cancer
Sx of thyroid cysts
haemorrhage into cyst = pain and rapid enlargement of nodule
a large cyst or extensive haemorrhage can = compression symptoms eg horarseness, dysphagia
Ix for thyroid cyst
US to assess size and appearance
FNA
plummer’s disease
hyperthyroidism with single toxic nodule - uncommon
